A 2-year-old Long Island girl was found dead in a pool Friday afternoon.

Suffolk County police found little Arlyn Vanegas-Luna unresponsive in the above-ground pool outside her next-door neighbor’s home on Chestnut Street in Brentwood at about 4:35 p.m. Cops said the neighbor is related to the girl.

The toddler was rushed to Southside Hospital, where she was pronounced dead.